Material Selection Assessment for Topside Process Equipment for Production Fluids with High CO2 Content

During recent years, in the exploration for new oil and gas sources, the tendency towards developing offshore fields in more stringent environments has increased. Operators are now developing deep water, high pressure, high temperature, and high CO₂ fields.  This tendency has created numerous challenges to the project initial cost (CAPEX) and subsequent operational cost (OPEX). The material selection is critical for such fields showing high CO₂ contents.  Although the initial capital cost for using carbon steel may be much lower than that of a corrosion resistant alloy (CRA), the total cost of the carbon steel option could be much higher due to the required severe corrosion inhibition programs and equipment failures representing losses not only by the cost of repairs, but also by the loss of production.

This paper addresses the material selection assessment for topside process equipment for production fluids with high CO₂ contents. Project specific cases are analyzed in terms of: 1) fluid/CO₂ partitioning through the topsides production systems, 2) corrosion analysis involving multiphase (oil, gas, and produced water), oil, gas, and produced water streams, and 3) the material selection for such piping and equipment.